Published 1968 | Version v1
Book

The Role of Amino Acids in Gluconeogenesis in Lactating Ruminants

  • 1. Department of Physiological Sciences, School of Veterinary Medicine, University of California, Davis, CA (United States)

Description

Gluconeogenesis has an important metabolic role in all animals, but it is especially important in ruminants because of the paucity of their alimentary glucose. Several amino acids give rise to glucogenic precursors during metabolism and thus dietary or body protein represents an important source of potential glucogenic material that the ruminant can utilize to manufacture the glucose required for its physiological functions. The role of various amino acids as glucose precursors has been evaluated in lactating ruminants by making a single intravenous injection of several different amino acids uniformly labelled with 14C and following, with time, the rate and extent of incorporation of 14C into the plasma glucose. The time interval after injecting each 14C-amino acid until the specific activity maximum occurred in plasma glucose was found to vary widely among the different amino acids. Thus, the maximum specific activity in plasma glucose occurred 6 min after injection of L-aspartate-14C and 15 min after injection of L-glutamate- 14C, while for L-valine-14C and L-arginine-14C the maximum specific activity in plasma glucose did not occur until 45 and 90 min, respectively, had elapsed. After injection of L-serine and L-alanine there were several maxima in the glucose specific activity. These maxima occurred between 12 and 24 min after injection of serine and during the first 30 min after injection of alanine indicating that carbon from these amino acids becomes available for glucose synthesis along diverse pathways which have different delays. Although only a few amino acids have been studied, the experimental results obtained clearly suggest an important metabolic role for protein in ruminants which has previously not been recognized. It appears that amino acids, released from protein, are utilized by the animal in a fashion which results in a prolonged availability of glucogenic precursors so that the animal can form glucose over long intervals of time. This characteristic of slowly providing potential glucogenic material should ensure more efficient utilization of the carbon for glucose synthesis. Data will be presented indicating the relative quantitative importance of the different amino acids as glucose precursors in lactating goats and cows. (author)

Additional details

Publishing Information

Publisher
IAEA
Imprint Place
Vienna (International Atomic Energy Agency (IAEA))
Imprint Title
Isotope Studies on the Nitrogen Chain. Proceedings of the Symposium on the Use of Isotopes in Studies of Nitrogen Metabolism in the Soil-Plant-Animal System
Imprint Pagination
360 p.
Journal Series
Proceedings Series
Journal Page Range
p. 247-261
ISSN
0074-1884

Conference

Title
Symposium on the use of isotope in studies of nitrogen metabolism in the soils-plant-animal system
Dates
28 Aug - 1 Sep 1967
Place
Vienna (Austria)

INIS

Country of Publication
International Atomic Energy Agency (IAEA)
Country of Input or Organization
International Atomic Energy Agency (IAEA)
INIS RN
44065902
Subject category
S60: APPLIED LIFE SCIENCES;
Resource subtype / Literary indicator
Conference
Quality check status
Yes
Descriptors DEI
ALANINES; ARGININE; CARBON; CARBON 14; COWS; GLUCOSE; GOATS; INTRAVENOUS INJECTION; LACTATES; METABOLISM; PLASMA; PRECURSOR; PROTEINS; SERINE; SYNTHESIS; VALINE;
Descriptors DEC
ALDEHYDES; AMINO ACIDS; ANIMALS; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; CARBOHYDRATES; CARBON ISOTOPES; CARBOXYLIC ACID SALTS; CARBOXYLIC ACIDS; CATTLE; DOMESTIC ANIMALS; ELEMENTS; EVEN-EVEN NUCLEI; HEXOSES; HYDROXY ACIDS; INJECTION; INTAKE; ISOTOPES; LIGHT NUCLEI; MAMMALS; MONOSACCHARIDES; NONMETALS; NUCLEI; ORGANIC ACIDS; ORGANIC COMPOUNDS; RADIOISOTOPES; RUMINANTS; SACCHARIDES; VERTEBRATES; YEARS LIVING RADIOISOTOPES;

Optional Information

Contract/Grant/Project number
Grant HD-02375; G-633-PATC-3
Lead record
qkr4n-73n55
Notes
34 refs., 2 tabs., 3 figs.
Secondary number(s)
IAEA-SM--97/30